Assigjjoes



Jan. 31, 1928. 1,657,910

s. B. ALLEN ET AL ELECTRICALLY OPERATED REMOTE CONTROL INDICATOR Filed Sept. 11. 1922 2 Sheets-Sheet 1 WITNESS: INVENTORS.

Jan. 31, 1928. s. B. ALLEN ET AL ELECTRICALLY OPERATED REMOTE CONTROL INDICATOR Filed Sept. 11, 1922 2 Sheets-Sheet 2 INVENTORS.

WITNESS:

tion; of thesaid indicator.

drawings.

Patented Jan. 31, 1928 UNITED STATES PATENT GFFKQE.

STRATFORD' B. ALLEN, OF FRAIIIINGHAM, AND LOBNE ROEERT SUTHERLAND, OF

BOSTON, Iv/IASSACHUSETTS, ASSIGNORS, BY MESNE ASSIGNMENTS, TO THE CLEVE- LAND TRUST COMPANY, TRUSTEE, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

ELECTRICALLY-OPERATED REMOTE-CONTROL INDICATOR.

Application filed September 11, 1922. Serial No. 587,608.

The objectof our invention is to provide an instrument whereby measurements or indications, may be established electrically at a distance from the origin of the condition to be measured or indicated, not being effected by a considerable variation in voltage of the actuating current, for illustration, such as would bethe casein using a storage battery whereby variable conditions exist, namely, noload, heavily loaded and maximum voltagewhile charging, also in.long distance transmission where there .is, likely tobe 2: considerable fluctuation in line voltage.

;The distinguishing featureof our inve'ntionis that it isnotappreciably affected by wide voltage variation provided that the minimum voltage-suppliedzis .sufiic'ient to render a full deflectionsof the pointer over the entire sea e-ot the instrument. WVe attain these objects 'b 'means of the mechanism illustrated e accompanying drawing, in which;- I Figure '1 is;a plan viewof' be essential parts of our electric; indicator. and their rein cross section.

lation to each ;o ther, .the coi ls being shown Figure 2 is a. side-elevation 'in cross sec- Figure 3.is-a diagram of the complete system.; I W

Figure 4 is-a diagram of a s imilar syst-em incorporating our principle but using a divided or split circuit.

Figure is a diagram showing the application of our-device to themeasnrementof enclosed and .storedfluids.,

Figure 6 illustrates diagrammatically the 'known and unknown resistances and galvanometer'of thensnal bridge-circuit are replaced by the double-wound solenoid or two electro-magnets in combination with means for indication, substantially as shown.

Similar reference numbers refer to like parts throughout the specification and 5 in its bearin relatively small cross section tremities in order that .they will become Our invention consists primarily in the following instrumentalitiesz- In Figures 1 and 2, the indicator com prises a base 1 on which are fastened pillars 2 and 3, which support the coil 4 through the means of the soft iron pole pieces 5 and 6 which in turn are held firmly to the ends of the coil 4 by its'soft iron core 31, said core being headed after passing through the pole pieces.- This combina-- tion constitutes the exciter field, and is secured to the pillars 2 and 3. by the screws 7 and 7". The angular frame 8 supports the double-wound solenoid 9 as well as the moving element comprised of the pivot 10 e, the armaturell and the pointer. 12 which moves over the scale 13.

Theseiews 14 and 15 are two terminals of the indicator. The third terminal 15 may be omitted by grounding its connections to .the base 1 where conditions permit a re- -t rn path from. the said base to the battery or energizing source.

-' The:soft iron pole pieces 0 and 6 are of at their exmagnetically saturated andestablish a relatively strong leakage field in the vicinity of the pole pieces. The opposed end portions otthe respectivepole pieces are also s ufiitive to the indicator vane for purposes of-ealibrating the-instrument by changing the relationot the pole pieces to thcindi cator vane.

In Figure 3 the same indicator illustrated in igure 1 is represented diagran'im'atically. Inaddition, wev show a source of electrical energy, in this case abattery (an alternating current can be substituted) and an ad- .ciently. malleable when made oflsoftiron, to 7 permit the adjustment'ot' thepole pieces rela justable bridge resistance 28 operated by means of a sliding contact arm 24.

One method of actuating thecontact arm 24: is illustrated in Figure 5. in. which is shown a schematic diagram of our device in operation.

' It is important that the action of a master float or other moving objectsuch, for example, as an elevator, penstock gate, etc, be suitably transmitted to the moving contact arm 24 in such a manner and in such ratio that the said contact arm will touch the resistance unit 28 at a point bearing a direct relation to the position of the master moving element, it being presumed that the latter will at all times be somewhere between two fixed points of limitation.

In Figures 3 and 4 for clearness of illustration, the windings of the several magnets and solenoid are shown as a few turns of wire. In practice they consist of'man'y' turns of fine wire wound to a considerable resistance, so that the current consumption of the indicator will be reduced to a minimum.

The followingservesas an explanation of the diagram shown in Figure Leading from the positive terminal of the'battery 26, the current which energizes the coil 29 flows through the conductors 2T, 16, terminal 14, thence through coil 29 to terminal 15, conductor 22, sliding cjo'nt aet 'arm 24, through thebridge resistance 28 to ground, or, if a three wire system is preferrechthrough conductors 23 and 17 to the negative terminal of the battery 26.

The coil 30 is wound upon the solenoid 9 in series with'coil 29, and with the same number of turns as the latter. As a matter of con 'enien ce the two wires may be wound at thesam'e time, However, in operation theyare in oppesition, since the 'current' flow 'is opposite in direction in the two windings. Thus 'incoil'30 tlie eurrent flows from the positive terminal of the battery 26 through conductors 27 and 25, thenc e through the bridge resistance 28, sliding contact arm 24, conductor 22, terminal 15, coil 30 to ground, or, in case a three wire system is preferred, through conductors 19, 18 and 17 to the negative pole of the bat.- t'ery 26.

During operation of the indicating system, current flows throughout the length of the bridge resistance 28.since said resistance is connected directly across the battery 26.

lVith the sliding contact arm 24 located as shown. namely, at the middle point of the bridge resistance 28, it is fair to assume that the current flow in the coils 29 and 30 is equal and opposite in direction, there being no flow or" current through the sliding contact arm 24: when at the middle point of the bridge resistance 28. Since the ampere turns of the said coils are equal, their magnetic fields are equal, but opposite, and consequently solenoid 9, comprising coils 29 and 30. is neutral inasmuch as the two opposed fields cancel. Ifno other means of controi existed, the armature 11 would not be under control under'the above condition, and the pointer 12 would stand at E on the scale 13, due to the fact that it is so balanced by the weight 46 that the moving element comprising the armature, pivot and pointer 12,

would not return the-pointer to E or zero,

the pointer in this case remaining at half "scale indication. Further, the use of a permanent magnet. for the establishment of an exciter field would result in serious error if not false indication upon slight fluctuations of voltage in the energizing circuit. lVe obviate these errors and undesirable conditions in our invention by the use of an el'ectro-magnet comprised of a coil 4 which energizes the soft iron core 31 and the pole pieces 5 and 6. This coil 4 is connected directly across the battery 26, its energizing current flowing from the positive of the battery 26 through the conductors 27, 16 terminal 14, conductor 20, the coil 4, conductor 21 to the ground, or in case a three wire system is employed, through conductors 32, 18 and 17 to the negative terminal of the battery 26.

By sliding the contact arm 24 to the end F of the bridge resistance 28, the current in the coil 30 will be greatlyincreased, since the half section of the bridge resistance 28 has been cut out, tending to throw coil 30 directly across the battery as the contact arm 24 approaches F. Likewise the current flowing in coil 29 will be correspondingly decreased, owing to the fact that the movement of the contact arm 24 toward the point. F on the bridge resistance 28 reduces the potential drop between the terminals 14 and 15 of the coil 29. said potential approaching zero at the position F of the contact arm 24. In other words. this position of the contact arm results in a short circniting of the coil 29 i In operation of the device the exciter field N-S generated by the magnet 4 tends to maintain parallel to itself the major axis of the armature 11 when the current flows equally but oppositely in the coils 29 and 30 of the solenoid 9, in which case the exciter field N-S is the only field acting on the armature ll. lVith the current flowing oppositely in direction through the coils 29 and 30, respectively, of the solenoid 9, it will be seen that when one of these coils (29 or 30) is the more strongly energizechthe armature 11 will rotate to a position where its maj r axis is approximately parallel to the resultant of the fields generated by the excite! poles NS and the solenoid 9.

Thus, it the relation between the coils 29 and 30 results in a north pole at the lower end of the solenoid 9, distortion of the field N S will follow, bringing about the establishment of a resultant field between the solenoid 9 and the pole S of the exciter field, to which the armature 11 Will become aligned, such process of alignment swinging the pointer 12 to F on the scale 13. In this case it is assumed for the purpose of illustration that the contact arm 24 is toward the end F of the resistance 28.

If, on the other hand, the sliding contact arm 24 is moved along toward the end E of the resistance 28 the pointer 12 will move proportionately along the scale 13, being virtually locked electrically to the contact arm 24, although the mechanism comprising the resistance 28 and the sliding contact arm 24 may be located at a point remote from the indicator. The operating current may vary in voltage without materially affecting the accuracy of operation of the indicator; furthermore, either direct or alternating current may be used, as a source of energy for the operationof the indicating system aforesaid, I "f In Figure 4 there is illustrated a variation in the mechanical construction of the indicator, as well as in its detailed application to a resistance having the qualities of-a voltage divider; Shown diagrammatically, this indicator comprises a POIIltQI 12 operatively connected to a pivotally mounted armature 11, said pointer arranged'to move over the scale 13.' The armature 11 isactuated by the field poles 41 and 42,-and" the-common pole 43. Poles 41-and 42 are separately connected to the lower endsof 'the'electro-magnets 35 and -39, the common-pole 43-connecting or bridging the upper ends of the said' electromagnets. -The electro-magnets35and=39 are wound with approximately theisame number of turns of wire, and are'socieonnecte d that they energize the pole ieces 41 and 42- with relatively "oppositepo arity, thus establishing a -field between poles 41 and 42 which controls themovement of-the' armature 11- -=In operation," curr'ent fiows 'fro'mth'e positive terminal ofi'the 'battery' through conductor 37 to the'cOntact 'a-rm 24g' then'cedi- -viding at the junction of-said contact arm and the resistance 28 and itlow ing' 'divergently through "said resistance 28 c0nductors 3(3 and 40,- the electro magnets 35 and 39, conductors 34 and 38,ret1irnst0"the negative pole of the battery 26 through the conductor 33. l'Vith the contact arm' 24 at'the -middle poi ntof the-resistance 28, it is evident that the voltages supplied to the electro-magnets '35 and 39 will be equal, rendering the commen-field pole 43 neutral in its relation to the field poles 41 and'42. Under the condition just described, the major axis of the armature 11 will tend to hold a position larallel to the field generated by the field poles 41 and 42. .v

field. And since the actuating and exciting field coils are common, being comprised in the electro-magnets 35.and 39, any variation in the voltage supplied to them will be compensated for in the relative strengths of the fields generated by the saidelectro-inagnets, causing the same angle of the resultant field to be -niaintainedfor a given setting of the sliding contact arm 24 on the resistance 28.

Figure 5 illustrates one application of our device to the measurement of enclosed or stored fluids. As here shown, the resistance 28 is cirmilar in shape, and the sliding contact arm 24 comprises a supporting hub 56, a collar 57 in which is mounted a ball contact 58. In operationthe rotation of the contact arm 24 about its. axis. 48 and on the resistance 28, causes proportional variation in the potentials. across the conductors 1G and 18, and conductors l8 and 22, resulting in differential energizationxof the actuating coils contained in the indicator, thereby causing the pointer 12 to change position according to the position of the sliding contact'arm 24. 1

Below Figure 5 is shown one method of adapting our transmitter to a tank containingzfluidto be measured. The sliding contact-arm 24 and the -resistancef28 are suitably. mounted-upon the;,tank 5,5., The said ucontactlarm is here shown operatively con- *nected to ashaft148 supported by a frame r47',-and through bevel gears 49 and 50.and thearm 53 to a float 51, thesaidfioat risingandgfallingwith' the surface of the liquids52 containedinfthe tank 55. Thus it will freadily be seen that uponivaryingtlie Ilh8ight'10f"tl'le liquid=52in flier-tank 55, the floatirmechanism willoperate the transmitter comprised of the-resistance 28 and the -slidingrcontact arnr24; and, by means 01 thesupply circuit comprising a hattery-26 and the conductors 27 and 17, bring about r-the cd-ordinating ofuthe position oli "the pointer 12 ;with the operatively connected float51 and the contact'arm 24. 3

'Figure 6 is a diagrammatic illustration of our indicating system, in which it is intended to point out its similarity in general principle to the .lVheatstone bridge circuit. An energizing'source is frepresented by the bat-- tery 26' across which is connectedthe bridge resistance 28-andthe coils 29 and 30 in series which, for purposes of illustration, may be considered as replacing the known and ,unknownresistances.- of the ordinary bridge circuit. A slidable contact arm 24 is connected from the middle point between the two coils 29 and 30 to the resistance In place of the galvanometer ordinarily employed to indicate balance in a bridge circuit, and usually connected between the sliding contact of the bridge and the junction of the known and unknown resistances, there are substituted the actuating coils 2.9 and 30 which, in conjunction with the exciter coili and field core 31, cause the pivotally moun ed armature 11 and the pointer 12 to move in relation proportionate to the lengths A and B on-tne bridge resistance 28. Thus a condition of balance or unbalance ot' the circuit is indicated by means of a mechanism comprised of the component parts of a bridge circuit, operatin upon the same general underlying principles of a Wheatstone bridge.

While the action of our device is in some respects similar as regards the indicator, to the conventional fixed-coil aniineters and voltmeters commonly used in automotive practice, it is easily recognized that its means of control are vastly difi'erent from the latter in that no permanent magnet is employed as an exciter, such permanent magnet employed in the construction of fixed-coil meters usually maintaining the pointer at the center of'the scale when no current is flowing. .VVhereas, in our device means are provided for returning the pointer to one end of the scale whenthe supply current is cut off, the excitenfield being deenergized and releasing the armature when the supply circuit is broken. Also, variations in voltage do not-:materially afl'ect the indication-of our device, since fieldstnengths proportionate to the voltage applied .are maintained betweenlthe-excite'r field andthe actuating coils. This wouldnot-be true in case a permanent magnetwere employed as the exciter. In View xofxtheit'oregoing explanation of ourindicating system audits operation, it should be'borne in mind that this indicator is not intended for 'thedirect measurement of current or potential, but rather as a relay or. remote-control indicator applicable to the transmission ofmea'surements to a point/remote fromthe source of said-measurements.

While we have shown and rde'scribed two forms of our invention we. do not' feel that they are modifications in the strict senseot' the word; they are onlyforms ofthefsame invention designed for different: purposes; and while the forms. shown. and'described exhibit our preferred construction we do notdesire to be considered as limiting ourselves to them alone. The principal feature of our invention resides in the fact that the exciter field, being an induced rather than a permanent field, creates .a condition of proportionate relation betweenitself: and

the field generated by the actuating coils under conditions of variation or reversal of potential, the resultant effect of which insures uniformity of performance under working conditions.

lVe claim:

1. In an indicating system, the combination of a base, an armature of the magnetic vane type pivoted on said base, an indicating member operatively connected to the pivotally mounted armature, an energizing source, an exciter magnet connected across the enei'gzing source, a bridge resistance, a solenod. for said armature having two parallel vindings producing opposing magnetic fields. the adjacent ends of said winnings are connected together at a common terminal, the opposite ends of said windings being separately terminated and connected to the opposite ends of the bridge resistance which in turn is connected across the energizing source common to the exciter magnet and the solenoid windings aforesaid, and a slidable contact operable with respect to the said bridge resistance and connected to the common terminal of the parallel windings of the double-wound solenoid.

npparaus for indicating at a distance the position of an element which has travel,

comprising an electro-mag-net fixed in position and in a circuit of substantially constant resistance producing a magnetic field; two equal control coils fixed in position and oppositely energized from separate variable cir cuits-in accordance with; the movement of said element having travel so as to affect oppositely the direction of the magnet field; and an indicating armature arranged to respond to variations in the direction of said field; the

said variable circuits being from the same source-of electric energy as the circuit for theelectro-magnet; and means responsive to the element having travel forvarying the currentsin the variable circuits whereby, the

armature is varied-indirection in accordance with the travel'of said element.

3. Apparatus for indicating at a;- distance the position of an eleiiient.\vhicl1 has travel,

comprising a source ofelectric energy, an

electro-magnet with poles fixed in position and energized from said source by a circuit of substantially. constant resistance, an indicating armature in. the field of said electroinagnet; two additional circuits from the same electrical source as that of the electroment which has travel, the magnetic effect of said coils being opposed in direction.

whosenormal directio 4. Apparatus for indicating at a distance the position of an element which has travel, comprising a source of electric energy, an electro-n'nignet having a pair of pole pieces or magnetic n'niterial energized from said source; an indicating armature movable in the magnetic field of said magnet; two variable circuits energized from the same electrical source as the magnetand each including a coil having a non-magnetic core arranged transverse to the axis of the field and i between the poles of the magnet, means for varying the-currents in the circuits in accordunce with movement of the element'having travel; said coils being wound to have their fields mutually opposite; the said poles of the magnet being thin and small relative to the magnetic'fiux to be carried, whereby there is alarge leakage field between the poles whose normal direction is controlled by these poles; said armature being out of alignment with said poles and positioned in the'leakage field-outside the axis'of the direct field" 1 i f 5. Apparatus for indicating at a;distan ce the position ofan element which-has travel, comprising a source of electricenergy, a magnet adapted to produce"a' magneti'c field of fixed direction; anin'di'cating-armature of the pivot-ed magnetic vane type positioned in the aforesaid agnetic field; a pairof difierentially energized circuits" eaclr' including' a coil, :1 sourceof"energy; 'means fo r varying the current in' said coils 'in accordance with the element having tfi'ave the said coils-have ing non-magneticcores arranged transverse tothe axis of the field between the poles of the magnetand bein'g wouhdto have their fields mutually opposite in f direction; 'the saiapages 5 o'f- 1 the finagnet beingi F thin and small relativeto'the magnetic fiuxitobe carried 'wl'1'ereby' there; is" a large leakage field 'coxitrolled by these poles the. armature" having a poir rter ar' ranged to stand at half-scale when-the currents thetwo coils are' equal; in

6. An 'iiidicating system eompr' ismg'" a source 'ofelectric energy, =a resistance e1 ment connected in 'sh'iint"relation'with the source 'of energy, a contact member, f'means for l n sa eco ac mem i ablne resistanceelement" accordance with m changes in the thing'being indicated, a magnetically actuated indicating mechanism remote from said resistance element, an energizing coil connected in shunt relation with respect to said source and producing a magnetic field proportional to the voltage of said source of energy, and a pair of connected actuating coils concentrically wound in opposed relation and connected in series relation across said source of energy and having their common point electrically connected to said contact member, said indicating mechanism being actuated by the combined influence of said energizing and said actuating coils.

7. An indicating system comprising a source of direct electric current, a resistance elementconnected in shunt relation with the source of energy, a contact member moved along sahl resistance element in accordance with changes in the thing being indicated, electromagnet means producing a magnetic field proportional to the voltage of said source, a second electromagnet means controlled. by the position of said contact member on said resistance element produciur a magnetic field angularly related to saio first field and reversible in polarity for extreme positions of the contact member, and magnetically responsive indicating mechanism controlled by the combined influence of said magnetic fields.

8. An indicating system comprising a pair of concentric and coaxial windings connected in series relation, a source of direct electric current for energizing" said windings, a' circuit; energized from said source of current including a resistance element connected to a point common to each of said windings, means for varying the position of the connection to said resistance element, a third winding energized from said source and producing a magnetic field in angular relation to the magnetic fieldt'produced by said pair of windings, and an indicating mechanism actuated by the combined influence of said windings in accordance with the variations in. the position of the connection to the said-resistance element. T? i i 1' 3 (9;An indicating system "comprising a source of direct electric current,a:pair of windings wound in opposed relation-and connected in' series relation across :s'aicl source of current, means connected to the common "point of said. windings for differ entially varying the degree of excitation of said windings, a third winding energi'zed from said source of energy and producing a magnetic'field proportional to thevoltagc of said source and invqu'adrature with the magnetic field produced bysaid pair of windings, and a magneticallyresponsive indicator adapted to be actuated by. the combined influence of said pair .of' windings and said third winding.

10. An indicating system comprising, a source of direct electric current, a pair of windings producing opposed magnetic fields, means for differentially varying the degree of excitation of each of said windings, the individual excitations of said windings being also proportional to changes in the voltage of said source, a third winding energized from said source and producing a magnetic field that is proportional to the voltage of said source and in angular relation to the magnetic field produced by said pair of windings, and magnetically re sponsive means actuated by the combined influence of said pair of windings and said third winding actuated thereby to a plurality of indicating positions.

11. An indicating system comprising a source of direct electric current, a pair of concentric and co-axial windings connected in series relation across said source of direct current, means for ditlerentialiy varycom )risino means establishin a substantially constant magnetic field, a magnetically responsiy e armaturepivotally mounted Within the zone of influence of said field, and a pair of co-axially arranged actuating windings jointly controlling the movement of said armature, and means varying the current in each of said windings in accordance with the thing being indicated, said windings being adapted to magnetically oppose each other.

13. An electro-magnetic indicating system comprising means establishing a substantially constant magnetic field, a magietically responsive armature pivotally mounted within the zone of influence of said field, a pair of concentrically and co-axially arranged actuating windings jointly controlling the movement of said armature. said windingsbeing magnetically opposed to each other. and means controlling the energization of one of. said windings in accordance with changes in the thing tovbe indicated in such manner thatthe energization of said controlled winding shall also be proportionately responsive to changes in the voltage of the source of electrical energy, and means correspondingly changing the 'energizationof the other \\-'inding in inverse relation in the first winding.

l-l. In an imlicating, system, the combination of a source of energy. a pivolally inountci l armature of the magnetic vane type, an indicating member operativcly connected to the pivotally mounted armature, means exciter field, a bridge resistance, a slidable contact for the resistance, actuating coils creating a magnetic field varying from like to unlike polarity with respect to a given pole of the relatively constant-exciter field, said actuating coils being controlled by the co-operat-ing bridge resistance having its slidable cont-actconnected by a lead to a terminal common to two ends of theseparate actuating coils, the two other ends of the actuating coils being connected to opposite ends of: the co-operating bridge resistance, said bridgercsistanee being connected by leads respdt ively extending 1 from its opposite ends, to the terminals of the energizing soured-said armature b'eing controlled by and moved With-respect to the resultant; magnetic fields generated-by said actuatingcoils and saidexeiter field, 4

15. An indicating infsitrumjentsystemcomprising means producing a magnetic field of substantially constantmagnetic intensity, solenoid m'ea'ns producing a-reversible magnetic field transversely ofthe first field and combining therewith -,to produce a resultant magnetic field,a pivotally mounted armature of 'the magnetic vane type acted upon by said'resultant field to swing said armature from one exterme.position through a n' ulr, tiplicity of intermediate indicating positions to the other extreme position, and means progressively changing the intensity and di rection' of said reversible magnetic field from'a maximum -,in one direction'to a corresponding maximum infthe other direction in response .to corresponding changes in the thingbeing indicated, the resultant magnetic field being of-grea-test intensity when the armature is at each end of its range of movement and being of minimum intensity for an intermediate position of the armature, said means for changing the: reversible field comprising a resistance unitconnected at each end to the system. and a contact member movable therealong in response to changes in the thing; heing'indicated electrically connected to said solenoid means.

STRATFORD B. ALLEN.

LORNE ROBERT SUTHICRLANI).

for producing a relatively constant 31 fill 

